Generating function
$$U_{1036}(x, y) = \frac{\left(1 - \sqrt{1 - 4 y}\right)^{3}}{8 y^{3} \left(1 - x\right)^{2}}$$
Explicit formula
$$T_{1036}(n, m, k) = \frac{3 k {\binom{2 k + n - 1}{n}} {\binom{3 k + 2 m - 1}{m}}}{3 k + m}$$
Data table
1 3 9 28 9 297 1001
2 6 18 56 18 594 2002
3 9 27 84 27 891 3003
4 12 36 112 36 1188 4004
5 15 45 14 45 1485 5005
6 18 54 168 54 1782 6006
7 21 63 196 63 2079 7007
Export
expand_less